• Journal of IKEEE
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• v.20 no.1
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• pp.107-110
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• 2016

In this paper, an IEEE 802.15.4 LR-WPAN 868/915 MHz ZigBee transceiver for IoT systems was designed and implemented. Non-coherent demodulation was exploited to satisfy ${\pm}80ppm$ frequency offset recommended in IEEE 802.15.4 LR-WPAN. Variable bitrate was supported according to operation modes. SPI module was embedded to connect various MCUs. The designed Zigbee transceiver was described in Verilog HDL and it was synthesized and verified in $0.18{\mu}m$ process. Its gate count was about 32,000 gates.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.853-854
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• 2007

센서네트워크는 유비쿼터스 사회에서 기반환경이 될 가장 중요한 기술 중 하나이다. 이러한 센서네트워크를 보다 효율적으로 관리하기 위해서는 IP 망과의 연동이 필수 적인 조건으로 부각되고 있다. 이러한 흐름에 맞춰 IEEE802.15.4 위에 TCP/IP 를 사용하기 위해 IETF 워킹그룹 6LoWPAN 이 만들어졌다. 본 논문에서는 IP 네트워크와 연동하는 센서네트워크(6LoWPAN)에서 센서의 특성에 따라 데이터를 효율적으로 요청하고 수집하는 프로토콜을 제안하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.365-368
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• 2012

본 논문은 기존 자동차 블랙박스 시스템에서 교통사고 현장정보를 분석할 때 좀 더 명확한 현장정보를 수집하기 위해 정보수집에 사용되는 각 센서(정보수집센서)의 설치 위치의 제약을 해결하고자 각 정보수집센서를 무선으로 연결하기 위해 WPAN(Wireless Personal Area Network)을 적용한 시스템을 설계한다.

• Information and Communications Magazine
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• v.28 no.9
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• pp.40-48
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• 2011

6LoWPAN은 IEEE 802.15.4를 기반으로 하는 센서 네트워크에 IPv6를 지원하기 위한 기술이다. 본고에서는 6LoWPAN WG에서 개발 및 논의되고 있는 기술 및 주요 쟁점을 소개하고, 6LoWPAN의 저전력 통신을 위해 에너지 효율을 높일 수 있는 duty cycle 제어와 관련된 중요한 요소들을 논의하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.659-660
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• 2009

Botnet은 공격자의 명령을 받아 공격을 수행하는 Bot과 bot을 관리하는 서버(혹은 peer)로 이루어진 네트워크이다. 유선 네트워크 상에서 Botnet을 탐지하기 위해서 많은 메커니즘이 제안되었지만 6LoWPAN과 같은 IP 기반의 센서네트워크 상에서 Botnet의 유형이나 탐지법에 대해서는 제안된 메커니즘이 없었다. 본 논문에서는 6LoWPAN 환경에서 Botnet의 공격 유형과 탐지법을 제안하고 구현 사례를 설명한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1497-1499
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• 2009

최근 들어 스팸 메일, 키 로깅, DDoS와 같은 공격에 Botnet이 사용되고 있다. Botnet은 크래커에 의해 명령, 제어되는 Bot에 감염된 클라이언트로 이루어진 네트워크이다. 지금까지 유선망의 Botnet을 탐지하기 위한 많은 기법이 제안되었지만, 현재 많은 개발이 이루어지고 있는 6LoWPAN과 같은 무선 센서 네트워크상의 Botnet에 관한 연구와 그 대처방안은 전무한 상태이다. 본 논문에서는 6LoWPAN 환경에서 Botnet이 얼마나 위험할 수 있는지 살펴보고 이를 탐지하기 위한 메커니즘을 제안하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2A
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• pp.176-186
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• 2006

In this paper, we propose an enhanced symbol detector algorithm for 2.45GHz LR-WPAN(Low-Rate Wireless Personal Area Network) receiver. Because the frequency offset of $\pm$80ppm on 2.45GHz band is recommended in IEEE 802.15.4 LR-WPAN(Low-Rate Wireless Personal Area Network) specification, a symbol detector algorithm having stable operation in the channel environment with large frequency offset is required. For robustness to the frequency offset, non-coherent detection-based symbol detector algorithm is typically applied in the LR-WPAN receiver modem. However, the noncoherent symbol detector has increased performance degradation and hardware complexity due to squaring loss of I/Q squaring operation. Therefore we propose a coherent detection-based symbol detector algorithm with frequency offset compensation using a preamble symbol. The proposed algorithm is more suitable for LR-WPAN receiver aimed at low-cost, low-power and low-complexity than the non-coherent symbol detector, since it can reduce performance degradation due to squaring loss of I/Q squaring operation and implementation complexity. Simulation results show that the proposed algorithm has performance improvement of about 1dB in various channel environments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.54-67
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• 2006

Low Rate WPAN (Wireless Personal Area Network) designed for low power and low cost wireless communication is an important technology to realize ubiquitous environment. IEEE 802.15.4 and ZigBee Alliance recommend the SKKE (Symmetric-Key Key Establishment) protocol for key establishment and management. The SKKE algorithm has security weakness such as the absence of authentication process or electric signature in key generation and exchange when devices join the role of coordinators. In this paper, we propose new key establishment and security algorithm based on public key encryption to solve low rate WPAN security problems. Also, to improve PLC AMR system's weaknesses in communication reliability and security, we propose a new AMR system model based on IEEE 802.15.4 and we apply our security algorithm to AMR profile for security enhancement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.49-56
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• 2006

This paper describes the design and the verification of IEEE 802.15.4 LR-WPAN 2.4GHz Physical layer for Ubiquitous Sensor Network(USN). We designed the Carrier Frequency Offset(CFO) compensation satisfied the frequency tolerance of IEEE 802.15.4 LR-WPAN and the adaptive matched filter that re-setting of the threshold for the symbol synchronization of the various USN environment. The multiplications is reduced 1/16 by this method each other at i, q phases and has 0.5dB performance improvement in detection probability. Proposed baseband system is designed with verilog HDL and implemented using FPGA prototype board.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.76-82
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• 2014

In order for heterogeneous unlicensed devices to co-exist on the same frequency band, the frequency interference avoidance mechanism is necessary. In this paper, a frequency interference between WLAN and WPAN systems that operate at 2.4 GHz ISM band was analyzed in the MAC layer. We observed that WPAN systems suffer from severe interference from WLAN systems. To avoid this interference problem, we propose a new channel shift algorithm for WPAN systems. We showed that the proposed channel shift algorithm is better than the traditional WPAN system which uses a fixed channel in terms of throughput.